Do i need extra prepositional phrase in this sentence to clarify him or her?

Question

I know in sentences with the direct / indirect object pronouns Les, Le, Las, Los, Lo and La , you need to put an extra prepositional prhrase in to clarify if it is her , him, it or you........so for this sentence , do i need to do that as well?

I lost her phone number Perdi su numero de telefono

since su can mean him or her, do i need to clarify with an addtional phrase?

Answer 1

Pepsi,

In conversation it might be clear from the context, in which case "Perdí su número de teléfono." by itself is fine. For example:

• Porqué no llamas a Maria?
• Perdí su número de teléfono.

On the other hand, if it's unclear from the context, it's also correct to say "Perdí su número de ella."

Answer 2

"Perdí su número de ella."........ Perdí el número de ella."......... no need for the "su"